Patents by Inventor Al Duerr

Al Duerr has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Brake system and controller for use with a wellhead direct drive
    Patent number: 11171580
    Abstract: The invention relates to fluid drive systems used in fluid wells and brake systems for permanent magnet wellhead direct drives. The braking controller connects or disconnects a brake resistor from a back EMF. A variable frequency drive (VFD) drives the motor and communicates with the control circuitry of the brake controller. The control circuitry monitors the brake resistor and depending on the rotational speed and direction of the motor and operating state of the VFD, disconnects or connects the brake resistor. If the direction of the motor is in reverse and above a threshold speed, it connects the brake resistor. If the direction of the motor is in reverse and below the threshold speed, the control circuitry dissipates stored back EMF through the brake controller. The amount of stored back EMF corresponds to the time to empty a pump.
    Type: Grant
    Filed: December 22, 2015
    Date of Patent: November 9, 2021
    Assignee: General Magnetic International Inc.
    Inventors: Al Duerr, Aaron Brassard, John Doyle, Wray Sparling
  • Brake System and Controller for Use with a Wellhead Direct Drive
    Publication number: 20170373613
    Abstract: The invention relates to fluid drive systems used in fluid wells and brake systems for permanent magnet wellhead direct drives. The braking controller connects or disconnects a brake resistor from a back EMF. A variable frequency drive (VFD) drives the motor and communicates with the control circuitry of the brake controller. The control circuitry monitors the brake resistor and depending on the rotational speed and direction of the motor and operating state of the VFD, disconnects or connects the brake resistor. If the direction of the motor is in reverse and above a threshold speed, it connects the brake resistor. If the direction of the motor is in reverse and below the threshold speed, the control circuitry dissipates stored back EMF through the brake controller. The amount of stored back EMF corresponds to the time to empty a pump.
    Type: Application
    Filed: December 22, 2015
    Publication date: December 28, 2017
    Inventors: Al Duerr, Aaron Brassard, John Doyle, Wray Sparling